With the successive promulgation of a number of national standards and further strengthening of vehicle waterproofing and other related requirements to improve vehicle safety, As one of the most perceivable performances by users, vehicle water management performance has been paid more and more attention by car companies. Intake manifold leak testing has become one of the key performance indicators in vehicle development. The intake manifold leak test use water to find air leak is suitable for artificial rain test based on natural conditions, without rain with strong wind speed, regardless of the high temperature of the sample and the large amount of water inflow caused by the temperature difference of the rain.
Water spray test will judge and identify (1) the effectiveness of the intake manifold or casing against rain penetration (2) the ability of the equipment to meet its performance requirements during or after exposure to rain (3) Physical damage to the inlet manifold due to rain (4) Whether the rainwater drainage system is effective. Through the analysis of the leakage water design problems that are easy to occur in the process of automobile product development, it is shown that the water management performance design can solve all the water management problems not only by improving the water sealing performance.
Meanwhile, It also reminds product design engineers, especially general layout, body-in-white and interior and exterior design engineers, to consider water sealing in water management when designing parts; Comprehensive application of strategies such as water conduction, drainage, and foreign body intrusion prevention for drainage facilities. The intake manifold vacume leak test engineer should establish an effective collaborative design mechanism with each component engineer to jointly determine the water management performance plan and reduce design errors.
What Are the Contents and Standards of The Vehicle Rain Test ? The automobile rain test has become an indispensable production link in the industry. The leak testing of air intake manifold refers to the water flowing into the car from the outside of the car body through the matching gap of the car body. The vehicle manufacturer uses artificially simulated rainfall environment to realize the rain sealing performance test.
Cars produced in China now generally use GB/T12480-1990 Test method for rainproof sealing of passenger cars｜Q/CAQ-16-2010 Commercial vehicle cab assembly rain tightness test specification｜QC/T476-1999 The limit of rainproof sealing of passenger cars｜The integrated and revised standard is QC/T476-2007 Limits and test methods for the rain-tightness of passenger cars. According to the requirements of GB/T12480-1990, the rainfall intensity of the rain test chamber is 4~10mm/min, the injection pressure of the nozzle is 69~147kPa, and the raining time is 15 minutes.
In the actual operation process, in order to strengthen the inspection of the rain sealing performance of the vehicle, the car manufacturers for automotive industry often increases the rain intensity by increasing the density of the nozzle and increasing the water spray pressure. The rainfall intensity of the rain test laboratory will be several times higher than the recommended value, and some manufacturers even exceed 100 mm/min. The spray pressure of the nozzle will also reach more than 200kPa, so that the spray water is atomized and sprinkled on the body.
At different stages of vehicle production, cars manufacturers have different test requirements for vehicles. During the trial production period of the vehicle, at this stage, since the production process and equipment parameters of the whole vehicle are in the test period, it is necessary to pass a long-term rain test (between 4 and 8 hours) of the whole vehicle to find out the parts that may leak, and then conduct water leakage cause analysis and design or process improvement.
When the whole vehicle is mass-produced, the design and process defects are basically improved, and routine inspections are mainly carried out in the rain to prevent the sealing defects caused by occasional non-compliance. Special vehicles such as power supply vehicles, vans, road sweepers, military equipment, etc., these vehicles have high requirements for water resistance. When necessary, especially for new product development, rain test is a necessary test link. Based on the type and practicability of the special vehicle, the rain test equipment for the special vehicle is designed and implemented.
In the actual operation process, in order to strengthen the inspection of the rain sealing performance of the vehicle, the car manufacturers for automotive industry often increases the rain intensity by increasing the density of the nozzle and increasing the water spray pressure. The rainfall intensity of the rain test laboratory will be several times higher than the recommended value, and some manufacturers even exceed 100 mm/min. The spray pressure of the nozzle will also reach more than 200kPa, so that the spray water is atomized and sprinkled on the body.
At different stages of vehicle production, cars manufacturers have different test requirements for vehicles. During the trial production period of the vehicle, at this stage, since the production process and equipment parameters of the whole vehicle are in the test period, it is necessary to pass a long-term rain test (between 4 and 8 hours) of the whole vehicle to find out the parts that may leak, and then conduct water leakage cause analysis and design or process improvement.
When the whole vehicle is mass-produced, the design and process defects are basically improved, and routine inspections are mainly carried out in the rain to prevent the sealing defects caused by occasional non-compliance. Special vehicles such as power supply vehicles, vans, road sweepers, military equipment, etc., these vehicles have high requirements for water resistance. When necessary, especially for new product development, rain test is a necessary test link. Based on the type and practicability of the special vehicle, the rain test equipment for the special vehicle is designed and implemented.
The main advantages of plastic intake manifolds are lower cost and lighter weight. In addition, due to the lower thermal conductivity of PA, HDPE than aluminum, the fuel nozzle and incoming air temperature is lower. The intake manifold can not only improve the hot start performance, increase the power and torque of the engine, but also avoid the heat loss in the pipe to a certain extent during cold start, and accelerate the increase of the gas temperature. And the smooth inner wall of the plastic intake manifold reduces air flow resistance, thereby improving engine performance.
In terms of cost, the material cost of plastic intake manifold and aluminum intake manifold is basically the same. The plastic intake manifold is formed at one time, with a high pass rate; The aluminum intake manifold blank casting yield is low, and the machining cost is relatively high. Therefore, the production cost of plastic intake manifolds can be reduced by 20%-35% compared with aluminum intake manifolds.
In terms of cost, the material cost of plastic intake manifold and aluminum intake manifold is basically the same. The plastic intake manifold is formed at one time, with a high pass rate; The aluminum intake manifold blank casting yield is low, and the machining cost is relatively high. Therefore, the production cost of plastic intake manifolds can be reduced by 20%-35% compared with aluminum intake manifolds.
| ● | High Temperature Resistance｜The plastic intake manifold is directly connected to the engine cylinder head, and the temperature of the engine cylinder head can reach 130~150℃. Therefore, the plastic intake manifold material is required to withstand a high temperature of 180°C. | Requirements for Plastic Material of Engine Intake Manifold |
| ● | Dimensional Stability｜The dimensional tolerance of the connection between the intake manifold and the engine is very strict, and the installation of sensors and actuators on the manifold must also be very accurate. | |
| ● | Chemical Stability Test｜The plastic intake manifold is in direct contact with gasoline and antifreeze coolant during operation. Gasoline is a strong solvent, and ethylene glycol in the coolant will also affect the performance of the plastic. Therefore, the chemical stability of the plastic intake manifold material is required. Very high and needs to be rigorously tested. | |
| ● | High Strength Requirement｜The plastic manifold is installed on the engine, and must bear the vibration load of the automobile engine, the inertial force load of the throttle valve and the sensor, the pulsating load of the intake pressure, etc., and also ensure that it will not be blasted by the high-pressure pulsating pressure when the engine is abnormally tempered. | |
| ● | Thermal Aging Stability｜The automobile engine works under very harsh ambient temperature, and the working temperature varies from 30 to 130 ℃. The plastic material must be able to ensure the long-term reliability of the manifold. |